Unexpected milk –
not a mammalian trait?
Lactating spider.
Caring mothers aren’t the first thing that spring to mind when you think about spiders. Yet plenty of evidence exists of female spiders providing food for their young and protecting their offspring. A recent and very surprising example of arachnid maternal care comes from a species of ant-mimicking jumping spider.
Chen et al (2018) observed female spiders secreting a nutritious milk-like substance, which the offspring first consume from the floor of the nest and once they are a bit older directly from the mother herself. Through a careful set of experiments the researchers found that the spiderlings are entirely dependent on this ‘milk’ for survival, and that there are still huge survival benefits to it even once they are old enough to forage independently.
Milk provision was once seen as an exclusively mammalian trait but this research adds to growing evidence that the practice is more widespread across animal taxa than previously thought.
Original research: http://dx.doi.org/10.1126/science.aat3692